KR20040106337A - Method of making a viscoelastic article by coating and curing on a resuable surface - Google Patents

Abstract

The present invention comprises the steps of coating a peeling surface with a curable composition; Contacting a second release surface with an exposed surface of the curable composition; And at least partially curing the composition. The composition is then removed from both peeling surfaces. Viscoelastic articles made according to these methods may be self-supporting.

Description

METHODS OF MAKING A VISCOELASTIC ARTICLE BY COATING AND CURING ON A RESUABLE SURFACE

Viscoelastic materials can be configured to possess a variety of different chemical and physical properties. As a result, viscoelastic materials can be useful for constructing a variety of articles for different applications. The variety of viscoelastic articles exists in certain manufacturing attempts to construct such articles, particularly for commercial applications where cost-effectiveness and large-scale manufacturing are particularly desirable. Manufacturing speed, consistency and reduced waste are all issues of concern for any commercial manufacturing process.

Articles comprising viscoelastic materials, such as pressure sensitive adhesives (PSAs), can be made using a variety of methods. For example, a transition tape comprising fragmented PSA can be constructed using an embossed carrier web to contain depressions in the surface of the carrier web. The depressions of the web can be coated using a peel coating. A curable composition (eg, a composition that can be cured to form a PSA) can be coated into depressions in the web on a release coating. A film composed of a cover sheet, such as polyethylene terephthalate (“PET”), is coated onto the curable composition and the web / composition / cover sheet assembly is exposed to UV radiation to cure the composition with PSA. The whole assembly is wound into a roll. When unwinding the assembly, the PSA adheres to the film cover sheet and peels away from the depression of the web to form a film coated with fragmented PSA in a pattern provided by the depression on the surface of the web. This method may not be desirable for making certain viscoelastic articles on a commercial scale because the web is not reusable and waste is generated, and the method is impossible to carry out continuously. The method must be stopped periodically to refresh the web material.

In another example, PSA-coated articles such as adhesive tapes and transition coatings can be constructed by extruding a coating of PSA on a molding tool. The surface of the PSA coating that is not in contact with the molding tool transfers the PSA to the substrate by contacting the substrate. The PSA of the resulting article retains the surface structure provided by the mold tool. In order to ensure clean separation of the PSA layer from the structured surface of the molding tool, the adhesion of the PSA to the substrate must be greater than the adhesion of the PSA to the surface of the molding tool. This method is limited to making viscoelastic articles that can be constructed from extrudable viscoelastic materials. In addition, this method does not provide a method of making a self-supporting viscoelastic article, i.e., a viscoelastic article, which may exist independent of the substrate used to remove the adhesive layer from the molding tool.

The PSA transition coating can be constructed independent of any support layer by coating the PSA layer on the release liner. The coated liner can then be wound up by itself to emboss the PSA layer using any structure that can be provided on one or both surfaces of the release liner. Subsequently, the transition coating is removed from the release liner to provide a transition coating independent of any type of support layer. This method cannot be run continuously because it must be stopped periodically to supply new release liners. In addition, this method is limited to the production of viscoelastic articles that may be composed of extrudable and embossable viscoelastic materials.

It may be desirable to make the viscoelastic article into the curable composition in a continuous manner. It may also be desirable to produce the viscoelastic article in a continuous manner independent of the support material. Current methods for producing viscoelastic materials from curable compositions cannot be performed in a continuous manner and do not allow for the continuous production of viscoelastic articles independent of the support layer.

There is a need for a continuous method of making a viscoelastic article from a curable composition, including the continuous manufacture of a viscoelastic article independent of the support layer.

The present invention comprises the steps of coating a peeling surface with a curable composition; Contacting a second release surface with an exposed surface of the curable composition; And at least partially curing the composition.

1 is a schematic diagram of an apparatus for making an article of the present invention.

Detailed Description of Exemplary Embodiments of the Invention

In order to describe the present invention in detail, the following definitions are used in the present specification.

By “cured composition” is meant any composition that is cured to any extent in total, ie, the cured composition may be partially cured or completely cured.

"Viscoelastic" means a material that exhibits both elasticity and viscosity. Elasticity refers to the ability of a material to respond to external stresses by deformation and to react by restoring the original shape of the material upon removal of stress. Viscosity refers to the ability of a material to react to external stress by continuing deformation as long as deformation and stress exist. The viscoelastic material may exhibit a transition from a fixed glassy state to a viscoelastic state at a temperature known as the glass transition temperature Tg. In addition, the viscoelastic material may be chemically or physically crosslinked to cause the viscoelastic material to be present in viscoelastic solid form. As used herein, examples of viscoelastic materials include, but are not limited to, PSAs, hydrogels, hydrocolloids, and hydrophilic gels.

"Viscoelastic article" means an article made of a viscoelastic material, for example a viscoelastic material that is cured to the desired degree for further use, examples of which include sheet materials and individual articles. As used herein, a viscoelastic article can be partially or fully cured.

The present invention provides a method of making a viscoelastic article, wherein the curable composition is prepared having a reusable first peeling surface configured to allow substantially continuous use of a manufacturing tool (eg, belt, roller or drum). Coated on the tool. Prior to curing the composition, the substrate having the second release surface is in contact with the composition coated on the first release surface. The composition is partially or fully cured, for example by photocuring. After the composition is partially or fully cured, both release surfaces are removed from the cured composition to produce a viscoelastic article that does not adhere to any type of backing. Alternatively, if the composition is partially cured and additional curing is needed, the partially cured composition may be removed from one peeling surface while still in contact with the other peeling surface. For example, the partially cured composition can be separated from the manufacturing tool while maintaining contact with the substrate. The curable composition may then be further cured while still in contact with the substrate. After the curable composition has cured to the desired degree, the resulting viscoelastic article can be removed from the substrate to provide a viscoelastic article that is not attached to any backing. Accordingly, the present invention provides a method of coating a curable composition on a reusable surface; Sufficiently curing the composition to form a viscoelastic article; A method is then provided that enables substantially continuous manufacture of one or more viscoelastic articles by a method comprising the step of removing the viscoelastic article from the reusable surface.

Thus, the process of the present invention allows for the continuous production of viscoelastic articles with less waste and reduced costs compared to the process of producing viscoelastic articles by coating and curing between two consumable substrates, for example release liners. do. In addition, the method of the present invention provides a method for producing a self-supporting viscoelastic article, ie a viscoelastic article capable of maintaining its strength and integrity without the aid of a substrate, for example a supportive backing.

The resoline in the practice of the method of the invention is schematically illustrated in FIG. 1. Curable composition 100 may be coated onto manufacturing tool 104 that includes a first release surface (not shown). In one embodiment, the curable composition 100 is coated through the feeder 102 by gravity or pressure. However, other methods of coating the curable composition 100 on the first peeling surface may also be suitable. Other methods of coating the curable composition on the first release surface include, but are not limited to, die coating and knife coating.

The manufacturing tool 104 can be any type of tool that can provide a reusable surface that can be configured to enable substantially continuous manufacture of the viscoelastic article 116. Examples of suitable forms of manufacturing tool 104 include, but are not limited to, belts, drums or rollers. This configuration may allow for substantially continuous manufacture of the viscoelastic article 116, because the curable composition 100 may be coated on the first release surface of the manufacturing tool 104 at the coating location 122. And the cured viscoelastic article 116 may be removed at the peeling location 124 to deposit the unoccupied surface portion 128 on the first peeling surface of the manufacturing tool available for recoating with the curable composition 100. Because it produces. The manufacturing tool 104 should be rotatable to enable the continuous manufacture of the viscoelastic article 116 according to the method of the present invention. The rotation of the manufacturing tool 104 may be operated by a motor, by hand, or manually operated, for example applied to another position in the manufacturing line that may cause or drive the rotation of the manufacturing tool 104. Can be operated by force.

Substrate 106 including the second peeling surface may be stored in roll 108 or directed onto idler roll 110. A correctly positioned nip roll 112 may be mounted to bring the nip roll 112 into contact with the manufacturing tool 104 as shown in FIG. 1. The substrate wraps around the nip roll 112 to form a nip between the first peeling surface on the manufacturing tool 104 and the second peeling surface on the substrate 106. The second peeling surface should retain low surface energy such that the viscoelastic article 116 can be substantially removed from the substrate 106. The curable composition is distributed between the first peeling surface (on the manufacturing tool 104) and the second peeling surface (on the substrate 106) to allow both peeling surfaces to contact. The first peeling surface, the second peeling surface, or both of the peeling surfaces may include a surface structure intended to impart a surface structure to the viscoelastic article 116. The exfoliation surface may be configured to retain a structured surface of the negative image that is complementary to the desired structure on the surface of the viscoelastic article 116.

Thus, the curable composition 100 coated between the first peeling surface and the second peeling surface may be cured using the energy source 114. Curable composition 100 may be cured to any desired degree, generally about 30-100%. The curable composition 100 must be sufficiently cured to be able to cleanly remove it from one or more peeling surfaces. If the curable composition 100 is insufficiently cured, it is too viscous and cannot be removed from the peeling surface without losing its integrity. If one of the peeling surfaces comprises a surface structure, the curable composition 100 must be sufficiently cured to preserve the surface structure imparted to the partially or fully cured composition. In certain embodiments, the curable composition 100 may be cured to about 50-100%, specifically about 60% to about 70%. However, the degree of cure desired for the specific application of the method of the present invention will depend in part on the ability of the partially cured composition to maintain the integrity of the composition.

Curable composition 100 may be cured by energy source 114 using, but not limited to, any suitable curing means, such as heat, infrared, ultraviolet, visible, or electron beam irradiation. Infrared radiation as described herein means non-particulate radiation having a wavelength range of 800 nm to about 3 mm. Ultraviolet radiation as described herein means non-particulate radiation having a wavelength range of about 200 nm to about 400 nm. Visible light irradiation refers to non-particulate radiation having a wavelength range of about 400 nm to about 800 nm. For electron beam irradiation, the dosage ranges from about 0.1 Mrad to about 10 Mrad.

In certain levels of irradiation, the rate of cure may vary depending on the permeability of the substrate 106 as well as the properties, density and temperature of the curable composition 100. It is possible to adjust the cure so that the surface of the curable composition 106 in contact with the substrate 106 cures to a greater extent than the curable composition in contact with the manufacturing tool 104. Curing control as described above may provide a cured composition that possesses desirable peeling properties for a particular application.

The partially or fully cured composition may be removed from the first peeling surface, the second peeling surface, or both. In one embodiment, the partially cured composition may be removed by the peel roll 118 at the peel position 124 while still in contact with the second peel surface (ie, the substrate 106). Once the viscoelastic article 116 cures to the desired degree, the viscoelastic article 116 is removed from the second peeling surface to provide a self supporting viscoelastic article that is independent of any support structure, such as a backing or liner. The partially cured composition may or may not be further cured by any second energy source 126. Suitable curing methods by the second energy source 126 are the same as described above for the energy source 116. 1 shows a viscoelastic article 116 collected on a roll 120 prior to removal from the substrate 106. Subsequently, the substrate 106 can be separated from the viscoelastic article 116 by any suitable means known in the adhesive transition art. Whether the partially cured composition performs curing with the second energy source 126 depends in part on the strength and viscosity required for the viscoelastic article 116 relative to the strength and viscosity of the partially cured composition.

In other embodiments (not shown), the partially or fully cured composition can be removed from the second peeling surface (ie, substrate) while still in contact with the first peeling surface (ie, the manufacturing tool). In such embodiments, the curable composition is partially or fully cured by an energy source as described above. The substrate can be removed, for example, by a roller or simply because the surface energy of the second peeling surface is very low. If the composition is partially cured, it may be further cured by a second energy source while still in contact with the manufacturing tool as needed. The viscoelastic article may be removed from the manufacturing tool by any suitable means to maintain the integrity of the viscoelastic article.

The curable composition can include any suitable composition that can be cured to form a viscoelastic material. Properties of viscous materials are described in John D. Ferry, Viscoelastic Properties of Polymers (John Wiley & Sons, Inc., 1980). Suitable curable compositions can be cured to form viscoelastic materials that are self supporting (ie, generally retain their form at room temperature) and are unable to significantly flow or extrude at room temperature. Such viscoelastic materials generally have a Tg of less than about 23 ° C. Certain curable compositions may form viscoelastic materials having a Tg of from about −100 ° C. to about 0 ° C. while forming a viscoelastic material having a Tg that is found to possess particular utility.

The resulting viscoelastic material may include PSA, hydrogels, hydrocolloids, hydrophilic gels (as described in WO 01/60296 published August 23, 2001) and combinations thereof. Examples of particularly useful viscoelastic materials are prepared from polymers and copolymers of acrylates, methacrylates, acrylamides, methacrylamides, hydroxy alkyl acrylates, hydroxy alkyl methacrylates, N-vinylpyrrolidinone and vinyl ethers. Hydrogels may be used. Additional hydrogels useful for practicing the methods of the present invention are described in U.S. Application No. ______ (Attorney Docket No. 57001US002) filed on the same date as the present application by the assignee herein.

The first release surface can be configured in any manner that allows for reuse of the surface in a continuous manufacturing method. For example, the first peeling surface can be the surface of a tool such as, but not limited to, a belt, roller or drum. The tool may be constructed of a peel material to provide a first peel surface, the peel material selected to provide sufficient peel properties to promote peeling of the cured composition from the tool. Examples of suitable release materials include, but are not limited to, silicone and fluorocarbon polymers. Alternatively, the tool may consist of any suitably supportive material, which may then be coated with a peel coating to provide a first peel surface. Examples of suitable release coatings include, but are not limited to, silicone and fluorocarbon polymers.

The substrate is cured after contact with the curable composition. Since the viscoelastic articles produced using the method of the invention can be self supporting, the substrate can be removed from the viscoelastic articles prior to use of the viscoelastic articles. Until contact with the curable composition and removal from the viscoelastic article, the substrate can provide support for the curable composition for partially cured compositions or for fully cured compositions. In addition, the substrate may be soluble such that the curable composition can be traversed along a post production line, such as a production line in contact with the first release surface or a treatment or storage of viscoelastic articles. The substrate may be composed of any suitable material capable of providing a support, optionally soluble support, to the cured composition. In addition, the substrate may be composed of a UV-transmissive material. In certain embodiments, the substrate can have low oxygen permeability to limit the diffusion of oxygen through the substrate. Oxygen diffused through the film can stop curing of the curable composition when the curing method includes radical polymerization.

The substrate comprises a second peeling surface and is constructed from, for example, a peeling material such as, but not limited to, a silicone polymer, a fluorocarbon polymer or a polyester film, such as polyethylene terephthalate ("PET"). can do. Alternatively, the substrate may be constructed from any suitably supportive material and may further include a release coating to provide a second release surface. The substrate thus coated may include, without limitation, a film, such as a polyester, polyethylene or polypropylene film having a silicone or fluorocarbon polymer release coating. The release material or release coating useful for providing the second release surface may be the same, and may be different from the release material or release coating used to provide the first release surface.

The release material or release coating provides a substrate having a manufacturing tool and a low surface energy, ie a first release surface and a second release surface, respectively. In one embodiment of the present invention, the first peeling surface has a lower surface energy than the surface energy of the second peeling surface. Thus, the cured composition will preferentially adhere to the substrate when the substrate is separated from the first release surface. The preferential peeling of the cured composition to the first peeling surface contributes to two factors: the adhesion of the cured composition to the first peeling surface and the adhesion of the cured composition to the second peeling surface. The preferential adhesion of the cured composition to the substrate rather than the first peel surface is characterized by the material used to make up the first peel surface, the material selected to make up the second peel surface and the substrate and the cured composition to the first peel surface. It depends in part on the degree to which the composition is cured prior to separation from it. In general, the partially cured composition can be more easily removed from the first peeling surface than the fully cured composition. For example, the partially cured composition can be easily removed from the first peeling surface and still adheres to the substrate having a second peeling surface of low surface energy. The fully cured composition is more difficult to remove from the first peeling surface, and if full curing is required, then the second peeling surface material needs to retain relatively high surface energy, for example by using a PET substrate.

In the embodiment of the present invention, shown schematically in FIG. 1, the cured composition adheres to the second release surface, ie, the substrate 106, when the substrate 106 is separated from the manufacturing tool 104. As a result, the first peeling surface, i.e., the manufacturing tool 104, can be recoated with a more curable composition in the continuous manufacturing method of the present invention. In addition, in this embodiment of the present invention, the partially cured composition may be delivered while still adhering to the substrate 106 to a location suitable for further curing by the second energy source 126 as needed.

Another feature of the method shown schematically in FIG. 1 is that the surface energy of the substrate is low enough so that the substrate 106 can be removed from the viscoelastic article 116 while maintaining the strength and safety of the viscoelastic article 116. Can be. Previous methods of curing a material to remove a viscoelastic article require that the cured material remain attached to a substrate, such as a backing, or the material may be two substrates, for example a release liner (finished article). Need to be cured). Thus, the method of the present invention at least partially cures the composition between a reusable surface (first peeling surface of a manufacturing tool) and a peeling surface of a substrate (second peeling surface), and the article from both the reusable surface and the substrate. Subsequently removing can provide a self supporting viscoelastic article. This means that (a) the cured composition will preferentially adhere to the second peeling surface when the substrate is removed from the manufacturing tool by the selection of the materials used to construct the first peeling surface and the second peeling surface, ( b) by enabling the viscoelastic article to be removed from the second peeling surface without damaging the article.

The reusable first peeling surface may be flat or may comprise a structured surface, such as a micro- or macro-repeat pattern. The reusable surface can include any suitable structured surface that is patterned or unpatterned. Examples of suitable structured surfaces include, but are not limited to, wells, pockets, ridges, channels, and the like. Any structure on the reusable surface will be a negative image of the desired structured surface on the viscoelastic article. For example, the ridges on the reusable surface will appear as channels in the surface of the viscoelastic article. In addition, the macrostructure in the reusable surface can reduce waste in the manufacture of viscoelastic articles. For example, the reusable surface may comprise a pocket array with flat surfaces between pockets. Such pockets may be of any desired shape, such as, but not limited to, oval, round, square, rectangular or triangular. In the method of the present invention, most curable compositions can be collected in a pocket and there is little or no curable composition in the flats, so that discs complementary to the shape of the individual viscoelastic articles, ie pockets with minimal cured composition between the pockets It is possible to manufacture. In some applications, it may be desirable to facilitate handling of viscoelastic articles by retaining a portion of the cured composition between pockets to provide a sheet of cured material connecting the individual viscoelastic articles. In other applications, it may be desirable to substantially remove the cured material from between the articles.

In addition, the primary structured surface (or primary structure) on the reusable surface may include a secondary structured surface (or secondary structure), a structured surface within the structured surface. For example, a primary structure, such as a pocket, on a reusable surface can include one or more additional structures, such as channels, within the primary structure. The secondary structure may be micro- or macro-scale. In one embodiment of the invention, the reusable surface comprises an oval pocket as the primary structure that holds the channel as a secondary structure on the bottom surface of the pocket. The individual viscoelastic articles produced are oval disks that include one or more surfaces that hold ridges.

In one embodiment, the primary structure on the reusable surface is about 0.51 mm deep, 2.5 cm long, end to end spaced about 0.5 cm apart, and intermittent depressions arranged in 178 rows around the circumference of the reusable surface. It includes a channel. Each row includes 170 channels, each channel being about 0.1 cm wide and about 0.3 cm from side to side across the width of the reusable surface. Each row of channels cancels out about 1.25 cm.

In another embodiment, the reusable surface comprises a continuous channel (not intermittent) of dimensional and lateral spaces as described above. In another embodiment, the reusable surface includes individual oval pockets that hold intermittent channels on the bottom surface of the pockets. The pocket is about 10.8 x about 9.2 cm and the short axis of the pocket is generally aligned along the longitudinal axis of the web. The oval pocket is about 0.76 mm deep and the channel is about 0.51 mm deep, providing a viscoelastic article of about 1.27 mm in total thickness. In one embodiment, the reusable surface provides a total of 224 oval pockets on the reusable surface, including four oval pockets and 56 oval pockets around the circumference of the reusable surface across the reusable surface. The pockets may or may not include a pattern of intermittent channels as described above in the pocket to provide a corresponding pattern of ribs on the surface of the viscoelastic article. If present, the channel may be micro- or macro-scale and may be oriented on the reusable surface in any manner suitable for the particular application. For example, the channel can be oriented substantially parallel to the minor axis of the oval pocket.

In one embodiment, the methods of the present invention can be used to construct an absorbent viscoelastic article having a saline Absorbency of at least about 100%. Brine uptake can be measured by weighing a sample of viscoelastic material to determine its dry weight W ₀ . The viscoelastic article may be contacted with an excess volume of 0.9% isotonic saline solution for 24 hours. The article was then removed from the brine solution, blot dried, and then weighed to obtain a wet weight W ₂₄ . Absorption rate (%) was calculated by the formula

% Absorption = (W ₂₄ -W ₀ ) / W ₀ x 100

The process of the invention may be useful for the production of viscoelastic articles having a structured surface and one or more particularly desirable properties. For example, the viscoelastic article may be a pressure sensitive adhesive ("PSA"), a hydrogel, a fluid (eg, water or wound effluent) absorbent polymer, or a combination thereof. For example, structured PSAs can provide (a) fluid control capacity for articles that are conformable to rough or irregular surfaces or (b) beneficial adhesion to the article or skin layer. In another example, the method of the present invention can be used to prepare an absorbent viscoelastic article in the form of an oval disc for use in wound dressings. Absorbent viscoelastic articles may include structured channels that facilitate dispensing fluid throughout the entire article mass, and the articles may also possess adhesive properties, such as PSA properties, as desired.

Summary of the Invention

The process of the invention allows for the continuous production of viscoelastic articles. In addition, the process of the present invention allows for the continuous production of articles made from cured compositions and self-supporting. The present invention provides a method of making a viscoelastic article wherein a composition curable to a viscoelastic material is coated on a first release surface of a manufacturing tool. The first release surface is reusable and is configured to enable continuous manufacture of viscoelastic articles. The substrate comprising the second peeling surface is in contact with the curable composition coated on the first peeling surface. The composition is at least partially cured, ie, typically the composition is partially or fully cured while the composition is in contact with the first and second release surfaces. Once the composition has cured to the desired degree, the viscoelastic article can be removed from one or both of the peeling surfaces as desired. Thus, the method of the present invention enables the production of viscoelastic articles independent of the support layer.

Accordingly, the present invention provides a method of making a viscoelastic article, wherein the method of the present invention

Providing a substrate having a second peeling surface and a manufacturing tool having a reusable first peeling surface configured to enable substantially continuous use of the manufacturing tool;

Coating a curable composition on a viscoelastic material on the first peeling surface to define an exposed surface of the curable composition;

Contacting the second peeling surface portion of the substrate with the exposed surface of the curable composition;

At least partially curing the curable composition;

Removing the at least partially cured composition from the first peeling surface; And

Removing the at least partially cured composition from the second peeling surface

It includes.

The curable composition may be partially or fully cured prior to removing the cured composition from one of the exfoliating surfaces. When partially cured, the cured composition may or may not be fully cured before being removed from other peeling surfaces. Thus, the cured composition may first be separated from the manufacturing tool or substrate and, if desired, may be fully cured before being removed from other peeling surfaces. The viscoelastic article may comprise pressure sensitive adhesive (PSA), hydrogel, hydrocolloid, absorbent material, or any combination thereof. The first peeling surface, the second peeling surface, or both of these peeling surfaces may comprise one or more structures, for example pockets, ribs, channels or microchannels. The article can be formed from a continuous sheet or an individual article, for example an oval disc.

Various other features and advantages of the present invention will become more apparent with reference to the following detailed description, examples, claims and appended drawings. In several places throughout the specification, guidance is provided through lists of embodiments. In each case, the cited list serves only as a representative group and should not be interpreted as an exclusive list.

The following examples are chosen merely to further illustrate the features, advantages and other details of the invention. However, while the examples are provided for this purpose, it should be fully understood that the specific materials used and the amounts and other conditions and details are exemplary only, and do not improperly limit the scope of the invention.

Belt manufacturers

Flexible silicone belts were made using techniques commonly used in the printing industry. Flexo-graphic printing plates with the same image as the desired pattern on the viscoelastic article were used as molds for making silicone belts. Silastic M silicone (Dow Chemical Company, Midland, Mich.) Was applied to the flexographic plate and cured. Nylon mesh scrim was placed on the cured silicone M silicone, a coating of silicone J silicone (Dow Chemical Company, Midland, Mich.) Was added and cured to give strength to the belt. The belts were glued together using RTV silicone.

Coating and Curing Apparatus I

A belt comprising a pattern of pocket structures on the surface was prepared as described above and used to construct a drum similar to that shown in FIG. A correctly positioned idler roll was mounted on top of the drum. The idler was positioned to contact the edge of the belt. A substrate, ie a polyethylene terephthalate ("PET") liner coated on both sides with a silicone release coating, was placed around the idler and placed on top of the drum forming a nip between the belt and the substrate. One side of the substrate formed a release surface configured to contact the uncured composition once the composition was coated onto the belt. The belt was driven and the drum was free to rotate using a pull roll.

Coating and Curing Apparatus II

Another polymerization apparatus included a patterned reusable silicone belt having a circumference of about 274 cm. The belt was mounted on two free rotating idler rolls (about 15.2 cm in diameter, about 110.5 cm apart from each other). The belt was about 20.3 cm wide and had a continuous pattern of continuous channels on its surface. The nip roll was correctly positioned on one of the idler rolls. A silicone-coated PET substrate was wrapped around the nip roll to form a nip between the belt and the silicone-coated substrate. A bank of Sylvania F20T12 350 BL fluorescent bulbs, 122 cm in length and about 6.4 cm in center, was placed on the silicone belt so that the bulbs were located about 7.6 cm above the belt. The release roll was placed on another idler roll. The substrate was introduced into a nitrogen inactivated chamber of about 9.1 m in length that wrapped 180 ° around the release roll and contained a bank of Sylvania F40T12 350BL fluorescent bulbs. The substrate was pulled into the pull roll at the end of the second bank of lights.

Example 1

A 90/10 mixture of isooctylacrylate / acrylic acid containing 0.1% Irgacure 651 (Ciba Specialty Chemicals Corporation, Tarrytown, NY) was degassed with a stream of nitrogen followed by a Sylvania F20T8 350 BLB fluorescent bulb Partially cured to a viscosity of 4500 cps. 2,6-Bistrichloromethyl-4- (3,5-dimethoxy-phenyl) -1,3,5-s-triazine (US Pat. No. 4,391,687) was added to the isooctylacrylate / acrylic acid composition. The final concentration was 0.15%, followed by thorough mixing to form a curable composition having a Tg of -30 ° C. The curable composition was coated onto the reusable silicone belt of the coating and curing device II described above. The silicone belt included a continuous channel pattern as described above. A differential silicone based Roparex 6250/6200 silicone liner (Roparex Inc. of Willowbrook, Ill.) Was placed on top of the curable composition coated on the belt using a nip roll having a gap of about 0.025 mm. The 6250 side of the substrate was in contact with the curable composition. The curable composition was partially cured using a bank of Sylvania F20T12 350BL fluorescent bulbs (EIT UVMAP, UV Integrated Radiometer, Sterling, USA) delivering an average intensity of 2.7 mW / cm ² at 141 mJ / cm ² . The partially cured composition and substrate were separated from the belt. The partially cured composition was further cured by passing through a nitrogen inactivated chamber containing an additional bank of Sylvania F20T12 350BL fluorescent bulb.

The resulting viscoelastic article was a patterned pressure sensitive adhesive ("PSA") containing ribs about 0.51 mm high with about 1 cm of space between the ribs. The total thickness of the PSA was about 0.56 mm.

A portion of the curable composition was coated in a portion of the belte that did not have a surface structure. This portion of the belt was about 0.25 mm thick and produced a flat PSA that retained good performance characteristics.

Example 2

20 parts by weight of N-vinylacetamide (Showa Denko, Tokyo, Japan), 73.76 parts of M-PEG 400 acrylate, 6 parts by weight of lauryl acrylate (Osaka Organic Chemical Company, Osaka, Japan), alpha methylstriene The curable composition containing 0.1 parts by weight of Aldrich Chemical Company, Milwaukee, Wisconsin and 0.14 parts by weight of Darocure 2959 (Ciba Specialty Chemicals Corporation, Tarrytown, NY) was degassed with a stream of nitrogen, and the Sylvania F20T12 350BL fluorescent bulb was Partially cured to a viscosity of 2250 cps. The resulting curable composition was coated onto a patterned reusable silicone belt using coating and curing device II. The silicone belt included a continuous channel pattern as described above. A differential silicone based Roparex 6250/6200 silicone liner (Roparex Inc. of Willowbrook, Ill.) Was placed on top of the curable composition coated on the belt using a nip roll having a gap of about 0.76 mm. The 6250 side of the substrate was in contact with the curable composition. The curable composition was 75% cured using a Sylvania 350BL F20T12 bank of fluorescent bulbs to deliver 141 mJ / cm ² in the average intensity 2.7 mW / cm ^2. The partially cured composition and substrate were separated from the belt. The partially cured composition was further cured by passing through a nitrogen inactivated chamber containing a bank of Sylvania F20T12 350BL fluorescent bulbs.

The resulting viscoelastic article was a patterned pressure sensitive adhesive ("PSA") containing ribs about 0.51 mm high with about 1 cm of space between the ribs. The total thickness of the PSA was about 1.02 mm.

Example 3

Premixed 28.74 parts by weight, methoxypolyethylene glycol 400 acrylate (Osaka Organic Chemical Company, Osaka, Japan), 29.8 parts, 2-hydroxyethyl methacrylate (Mitsubishi Rayon Company, Tokyo, Japan) 11.26 Parts by weight, curable composition containing 0.16 parts by weight of Darocure 2959 (Ciba Specialty Chemicals Corporation, Tarrytown, NY) was degassed with a stream of nitrogen and partially cured to a viscosity of about 2200 cps using a medium pressure bulb. The premix was prepared with 17.4 parts by weight of Gantrez S 95 resin (International Specialty Products, Wayne, NJ) and 82.6 parts by weight of 2-hydroxyethyl methacrylate (Mitsubishi Rayon Company, Tokyo, Japan). 0.04 parts by weight of Irkacure 819 (Ciba Specialty Chemicals Corporation, Tarrytown, NY) was added to the partially cured material and then mixed to form a curable composition with a Tg of -47.9 ° C. for coating onto a reusable silicone belt. It was. The belt included an intermittent channel pattern as described above. The spreading of the curable composition was adjusted across the width of the belt by about 18 cm using an edge dam. Loparex silicone based 6200 / 4320C (Roparex Inc. Willowbrook, Ill.) Was placed on the curable composition coated on the belt. The 6200 side was in contact with the curable composition. The composition was cured to about 70% using the coating and curing apparatus I to expose to UV irradiation 336 mJ / cm ² at an average intensity of 3.7 mW / cm ² . The belt speed was about 3.7 m / min.

The partially cured viscoelastic article and substrate were removed from the belt by separating the substrate from the belt. A thin film of uncured material remained on the belt after the partially cured material was removed.

Example 4

15 parts by weight of poly (ethylene glycol-ran-propylene glycol) dimethacrylate (reaction product of UCCN 75-H-90,000 (union carbide of Carlston, West Virginia) and methacrylic anhydride), 2-hydroxy 20 parts by weight of ethyl methacrylate (Mitsubishi Rayon Company, Tokyo, Japan), 65 parts by weight of methoxypolyethylene glycol 400 acrylate (Osaka Organic Company, Osaka, Japan), alpha methylstriene (Aldrich, Milwaukee, WI) The curable composition containing 0.1 parts by weight of Chemical Company) and 0.16 parts by weight of Darocure 2959 (Ciba Specialty Chemicals Corporation, Tarrytown, NY) were degassed with a stream of nitrogen and parted at a viscosity of about 1000 cps using a medium pressure bulb. Cured. 0.04 parts by weight of Irkacure 819 (Ciba Specialty Chemicals Corporation, Tarrytown, NY) was added to the partially cured material and then mixed to form a curable composition with a Tg of -50.2 ° C. for coating onto a reusable silicone belt. It was. The resulting curable composition was coated onto a reusable silicone coated belt containing an oval pocket surface structure as described above. The spreading of the curable composition was adjusted across the width of the belt by about 18 cm using an edge dam. Loparex silicone based 6200 / 4320C (Roparex Inc. Willowbrook, Ill.) Was placed on the curable composition coated on the belt. The 6200 side was in contact with the curable composition. The composition was cured to about 70% using the coating and curing apparatus I to expose to UV irradiation 336 mJ / cm ² at an average intensity of 3.7 mW / cm ² . The belt speed was about 3.7 m / min.

The partially cured viscoelastic article and substrate were removed from the belt by separating the substrate from the belt. A thin film of uncured material remained on the belt after the partially cured material was removed.

Example 5

Poly (ethylene glycol-ran-propylene glycol) dimethacrylate (UCCN 75-H-90,000 (reaction product of Union Carbide, Carlston, West Virginia) with methacrylic anhydride) 15.4 parts by weight, 2-hydroxy 16.6 parts by weight of ethyl methacrylate (Mitsubishi Rayon Company, Tokyo, Japan), 67.7 parts by weight of methoxypolyethylene glycol 400 acrylate (Osaka Organic Company, Osaka, Japan), alpha methylstriene (Aldrich, Milwaukee, WI) The curable composition containing 0.1 parts by weight of Chemical Company) and 0.14 parts by weight of Darocure 2959 (Ciba Specialty Chemicals Corporation, Tarrytown, NY) was degassed with a stream of nitrogen for 15 minutes, and vigorously stirred with a medium pressure mercury bulb. Partially cured to a viscosity of about 1000 cps. 0.04 parts by weight of Irkacure 819 (Ciba Specialty Chemicals Corporation, Tarrytown, NY) was added and mixed. The resulting curable composition was coated onto a reusable silicone belt about 51 cm wide. The silicone belt contained intermittent channels as described above, but the channels were grouped in three lanes. One lane was about 11.4 cm wide, the second lane was about 19.0 cm wide, and the third lane was about 15.2 cm wide. The lanes were about 0.6 cm apart. Each lane contained a number of channels about 2.5 cm long and about 0.1 cm wide. The channels in one lane were about 0.5 cm apart and about 0.3 cm apart.

The curable composition was partially cured using the coating and curing device I to expose to UV irradiation 289 mJ / cm ² at an average intensity of 1.6 mW / cm ² . Loparex silicone base 8500/8500 (Roparex Inc. Willowbrook, Ill.) Was placed on the curable composition coated on the belt. The belt speed was about 1.8 m / min.

The partially cured composition and substrate were removed from the belt by separating the substrate from the belt. A thin film of uncured material remained on the belt after the partially cured material was removed. Part of the cured composition and cured further by using the Sylvania 350 BL F40T12 fluorescent light bulb to pass 3842 mJ / cm ² in the average intensity 6.6 mW / cm ^2. This process produced a fluid adsorbable patterned viscoelastic article of about 1.02 mm thickness useful for constructing a medical dressing.

Patents, patent documents, and publications cited herein are incorporated by reference in their entirety, as mentioned at the time of citation. In case of conflict, the present specification, including definitions, will control.

Various modifications and variations of the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. It is to be understood that the invention is not inadequately limited by the exemplary embodiments and examples described herein, which are merely exemplary and the scope of the invention is defined by the appended claims. It is decided.

Claims (28)

Providing a manufacturing tool having a reusable first peeling surface and a substrate having a second peeling surface configured to enable substantially continuous use of the manufacturing tool; Coating a curable composition on a viscoelastic material on the first peeling surface to define an exposed surface of the curable composition; Contacting the second peeling surface portion of the substrate with the exposed surface of the curable composition; At least partially curing the curable composition; Removing the at least partially cured composition from the first peeling surface; And Removing the at least partially cured composition from the second peeling surface Comprising, at least one viscoelastic article. The method of claim 1, further comprising further curing the composition after removing the at least partially cured composition from the first peeling surface, but before removing the composition from the second peeling surface. Way. The method of claim 1, further comprising further curing the composition after removing the at least partially cured composition from the second peeling surface, but before removing the composition from the first peeling surface. Way. The method of claim 1, wherein the first release surface comprises a first release coating. The method of claim 4, wherein the first release coating comprises a silicone polymer or a fluorocarbon polymer. The method of claim 1, wherein the second release surface comprises a second release coating. The method of claim 6, wherein the second release coating comprises a silicone polymer or a fluorocarbon polymer. The method of claim 1, wherein curing of the curable composition comprises photocuring. The method of claim 1, wherein the viscoelastic material comprises a hydrogel. The method of claim 9 wherein the hydrogel is an acrylate, methacrylate, acrylamide, methacrylamide, hydroxy alkyl acrylate, hydroxy alkyl methacrylate, N-vinylpyrrolidinone, vinyl ether, or any thereof One or more polymers or copolymers prepared in combination. The method of claim 1 wherein the viscoelastic material comprises an absorbent material. The method of claim 11, wherein the absorbent material has a Saline Absorbency of at least about 100%. The method of claim 1, wherein the at least one first peeling surface and the second peeling surface comprise a structured surface. The method of claim 13, wherein the structured surface comprises a plurality of channels. The method of claim 14, wherein the channel is a microchannel. The method of claim 13, wherein the structured surface comprises one or more primary structures. The method of claim 16, wherein the at least one primary structure comprises a secondary structured surface. The method of claim 17, wherein the secondary structured surface comprises a plurality of channels. 19. The method of claim 18, wherein the at least one channel is a microchannel. The method of claim 16, wherein the primary structure comprises a pocket capable of collecting the curable composition. The method of claim 20, wherein the pocket further comprises a secondary structured surface. The method of claim 21, wherein the secondary structured surface comprises a plurality of channels. The method of claim 1, wherein a plurality of individual articles are made. The method of claim 23, wherein the individual article comprises an ovoid disk. A viscoelastic article made by the method of claim 1. 27. The article of claim 25, wherein the article comprises an oval disk. 27. The article of claim 26, further comprising one or more ridges or one or more channels. The article of claim 25, wherein the article has a saline absorption rate of at least about 100%.